This invention relates to a storable and shippable composite cartridge containing, in separated condition therein, at least two different fluid compositions which cure on being mixed together. The invention also relates to structural components for making such a cartridge. It further relates to the combination of such a cartridge with apparatus for metering extrusion of its contents, and to the apparatus as a separate entity.
Many two part curable systems are now widely used in a variety of applications, especially as adhesives, bonding agents, potting agents, structural fillers, coatings, seals, liners, and the like. Such systems generally consist of a fluid composition which suitably may be characterized as being resinous, plus another fluid composition which suitably may be characterized as a hardener. Pigments, plasticizers and other modifying ingredients may be incorporated as a part of either or both of the two main parts of the two part systems. When the two different fluid compositions are homogeneously mixed together, the resulting mass cures (that is, hardens or reacts) to form a relatively solid non-moldable mass, which may vary in character from a brittle mass to a highly elastomeric one. The curing takes place generally at room temperature, although elevated temperatures hasten it. Many two part systems which cure under ambient or room temperature conditions exhibit extraordinarily desirable properties; but they have heretofore been very messy for the user to handle. Additionally, unless special precautions are taken by the user, costly wastes of prematurely cured material or clogged bulk mixing equipment may be encountered.
Heretofore proposed devices or cartridges for two component systems have been defective for one or more reasons. They have required intermixing of the components within the cartridge or within one end of the cartridge assembly before extrusion, which then requires immediate use of the entire contents or waste of non-used material. Some have employed collapsible tubes, which give unreliable results and do not permit accurate metering extrusion, especially when different viscosity materials are packaged. All known cartridges lack separated passages through a protruding neck, and thus do not permit the preserving of a partially spent cartridge for use at a later time.
Apparatus for extrusion has heretofore lacked the combination of features required for controlled metering extrusion of coaxially packaged two part systems, and has especially lacked the combination of coaxial plungers, cartridge holding means, and plunger advancing means as taught herein.